[build] Add bash script to get git repo info.
[build] Added git info processing in the configure step.
[x264] Added a script to get the most recent x264 encode library.
[x264] Revert "x264: hardcode the version string so that the full and correct x264 version is used in encoder/set.c, regardless of the tarball (full git repo vs. git archive) or where HandBrake is built from (source tarball vs. svn or git checkout)."

This reverts commit 2190aa047bb1b9eac2d31bcf7155dbb15d9d2eb5.

I use the direct x264 version plus some info of my own.
[x264] Bump to x264-r2356-a1d3d17